This invention relates to a needle plate for a cut pile tufting machine, and more particularly to a needle plate mounted on the hook bar of the cut pile tufting machine.
One of the essential parts of practically any multiple needle tufting machine is a support for the base fabric as it moves longitudinally through the machine, and particularly as it moves beneath the needles. The base fabric requires support as the needles penetrate the fabric, which tends to force the base fabric down. Moreover, the base fabric needs to be supported as long as the loops carried by the hooks remain on the hooks, because the tension in the loops carried by the hooks exerts downward pressure upon the base fabric.
The most common and prevalent device for supporting a base fabric as it moves toward and beneath the needles in either a cut pile or a loop pile machine is the conventional needle plate. The needle plate includes a base plate mounted in front of the needles and supporting a plurality of rearward projecting needle plate fingers which extend between the needles in order to hold the base fabric while the needles penetrate the base fabric. Such basic needle plate fingers function very satisfactorily in multiple needle tufting machines in which the needles are in-line.
In multiple needle tufting machines in which the needles are staggered, whether cut pile or loop pile, the front needles are adequately supported by the rearward projecting, conventional needle plate fingers. Moreover, where the needle gauge is not too narrow, the needle plate fingers may project rearwardly far enough and be large enough to adequately support the base fabric as the rear needles penetrate the base fabric.
However, for finer needle gauges, which have become more prevalent in recent years, problems arise in supporting the base fabric in the area of rear-needle penetration because needle plate fingers which are large enough to adequately support the base fabric tend to crowd the area in which the tufts are formed. Furthermore, straight needle plate fingers which project rearwardly easily between the front needles are obstructed by the rear needles, requiring adjustments in the shapes of the needle plate fingers.
One solution to the problem of extending needle plate fingers between staggered needles is solved in the prior R. T. Card U.S. Pat. No. 2,976,829, in which the needle plate fingers are bent to provide substantial equal spacing between the needle plate fingers and the front and rear needles.
In multiple needle tufting machines in which two or more transverse needle bars are longitudinally spaced in the direction of fabric feed, supporting the base fabric as it moves beneath the extensively spaced needles presents fabric support problems which are not readily solved by the conventional needle plate, even with extended needle plate fingers of sophisticated shapes.
In the Fedevich U.S. Pat. No. 2,889,791, issued June 9, 1959, a pair of front and rear transverse needle bars, supporting respectively a plurality of transversely spaced front and rear needles, are shown cooperating with longitudinally spaced rows of looper hooks for forming two transverse rows of loop pile tufts simultaneously. In the Fedevich patent, the base fabric is supported by a plurality of longitudinally extending transversely spaced grating strips 29 which are supported at their front and rear ends by the end transverse bars 26 of grating plate sections 27. It appears that the grating strips 29 are longitudinally straight. Moreover, because of the longitudinal span of the grating strips 29, a minimum thickness of each strip 29 would be required to provide a stable support for the base fabric W.
In the Gebert U.S. Pat. No. 3,025,807, again two sets of longitudinally spaced needle bars supporting needles which cooperate with a front set of cut pile hooks and a rear set of loop pile hooks includes a throat plate 15 for supporting the rearwardly moving base fabric F. Although there is a limited disclosure of the throat plate 15, nevertheless, it appears to be of similar structure to that disclosed in the above Fedevich patent.
The Rodstein et al U.S. Pat. No. 3,402,686 discloses another tufting machine incorporating a pair of longitudinally spaced needle bars supporting needles which cooperate with two sets of corresponding cut pile hooks for forming two transverse rows of cut pile. In this patent, the base fabric 132 is supported by a fabric support or grate, which is unnumbered, but which appears to span the front and rear bed plates 138. As viewed in FIG. 5, Rodstein et al appears to disclose a plurality of transversely spaced straight longitudinal fingers or grate bars extending between the needle paths, for supporting the base fabric 132. In other words, the fabric support in Rodstein et al appears to be similar in construction to those disclosed in the Fedevich and Gebert patents. The base fabric 132 is additionally supported in Rodstein et al by the feed dogs 136 periodically as they move upward into engagement with the base fabric 132 to move the fabric rearward.
In U.S. Pat. No. 4,754,718 for "DOUBLE NEEDLE BAR TUFTING APPARATUS FOR THE FORMATION OF LOOP PILE AND CUT PILE", issued July 5, 1988 to Charles W. Watkins, and having a common assignee with this application, the base fabric moves beneath the two rows of needles supported in longitudinally spaced front and rear needle bars 12 and 13. A portion of the base fabric 28 beneath the front needles 14 is supported by a conventional needle plate having conventional needle plate fingers 26 which project between and rearwardly of the front needles 14. However, the rear portion of the base fabric 28 is supported upon a plurality of needle plate fingers 74 which are fixed to the corresponding cut pile hooks 31 in front of the rear needles and project rearwardly between the rear needles.
In the common assignee's co-pending application Ser. No. 150,759, filed Feb. 1, 1988, for "DOUBLE NEEDLE BAR LOOP PILE TUFTING APPARATUS", by the same inventor Charles W. Watkins, FIGS. 10 and 11 disclose another fabric support structure used during the formation of a pair of longitudinally spaced loop pile tufting mechanisms. FIGS. 10 and 11 disclose the front portion of the base fabric 35 being supported by conventional needle plate fingers 134 beneath the front needles 14. The rear portion of the base fabric 35 is supported beneath the rear needles 15 by a plurality of forward projecting needle plate fingers 135 which are fixed to the rear loop pile hooks 142. Thus, the rear needle plate fingers 135 move simultaneously with and are spaced above the bills of the rear loop pile hooks 142 for continuously supporting the base fabric portion beneath the rear needles 15.
The common assignee's U.S. Pat. No. 4,671,194 for "LOOPER APPARATUS FOR EQUALIZING THE LEGS OF CUT PILE TUFTS", issued June 9, 1987, discloses uniquely shaped cut pile hooks having offset portions and also needle plate fingers having offset portions cooperating in such a manner as to produce cut pile tufts having legs of equal length or depth.